ECR Spotlight – Takahira Okuyama Free

Takahira Okuyama

How did you become interested in biology?

My interest in biology was sparked during my early childhood. I grew up in Yamagata, a rural area in Japan surrounded by rich nature – mountains, rivers and forests. While many of my classmates were busy battling Pokémon on their Nintendo DS, I was out in the woods, covered in mud, trying to catch beetles. I was always fascinated by living creatures, constantly bombarding my parents with questions they couldn't answer. One pivotal experience came when I was in elementary school. For a summer vacation assignment, I decided to observe an ant nest that had formed in our garden. I noticed that different ants seemed to be performing different tasks – some carried food back to the nest, while others clean up trash from the nest. Curious about whether these ants consistently performed the same roles, I devised an experiment. I marked individual ants using acrylic paint: white for food carriers, red for waste removers. To my amazement, even on the following days, the same ants continued doing the same jobs. That moment of discovery – the realization that even seemingly chaotic animal behaviour followed an ordered structure – was unforgettable. It was then that I felt the thrill of scientific discovery in behavioural ecology for the first time. I realized that even though animals don't speak, with the right approach, experiments can allow us to ‘listen’ to them and understand their behaviour. That early experience continues to shape my scientific curiosity. After entering university, my interest in collective animal behaviour deepened, eventually leading me to pursue research in behavioural ecology, where I now study the behavioural dynamics within species such as Drosophila.

Describe your scientific journey and your current research focus

My scientific journey began in the Laboratory of Functional Ecology in Chiba University, where I currently belong, with a project investigating the collective behaviour of fruit flies. As a third-year undergraduate at the time, I was overwhelmed by the huge amount and variety of tasks I faced: maintaining nearly 100 genetically distinct fly lines, conducting behavioural experiments with Python-based video recording, and analysing the resulting data through tracking and behavioural quantification. Through these experiences, I developed not only practical skills in behavioural analysis and large-scale data processing but also the mental resilience and critical thinking skills that are essential for scientific research. The findings from this initial project laid the foundation for my first research article, which has now been published in Journal of Experimental Biology. During the course of this project, I began to develop a hypothesis that the effects of heterogeneity are environment dependent – that is, genetic heterogeneity may exert stronger effects under conditions of environmental heterogeneity. This insight has since shaped the direction of my current research. I am now investigating the interactive effects of genetic and environmental heterogeneity on collective behaviour using a custom-designed maze system for fruit flies. In addition, I am placing increasing emphasis on uncovering the molecular basis of heterogeneity effects and exploring their relevance to evolutionary processes. To pursue this research theme, I have been expanding my skill set beyond behavioural analysis to include genetic profiling and experimental evolution approaches. This new phase of my scientific journey is both challenging and exciting. I see it as an opportunity to bridge behaviour, genetics and evolution to better understand how biological diversity shapes group-level outcomes. Although I am still at the beginning of this path, I am committed to deepening my scientific insight and contributing to the broader understanding of behavioural ecology.

How would you explain the main findings of your paper to a member of the public?

When we think of collective animal behaviour – like a school of fish, a flock of birds or even a group of flies – many theoretical studies have often assumed that the individuals should act in the same way. But in reality, even members of the same species can differ in how they move, explore or interact with others. In our study, we explored how such diversity within a species affects group behaviour, using approximately 100 strains of Drosophila melanogaster, one of the most studied species in behavioural research, and examined the behavioural mechanism of diversity effects. We observed how different groups of flies explored an open arena. Homogeneous groups consisted of a single strain, while heterogeneous groups were made by mixing two genetically distinct strains. We evaluated their speed, how thoroughly they searched the area, where they preferred to stay and how long they stopped. What we found was striking: genetically mixed groups (heterogeneous groups) did not simply move as an average of the two strains. Instead, they often showed new patterns of behaviour that couldn't be predicted by looking at the single strains (homogeneous groups). For example, heterogeneous groups tended to explore the centre of the arena more and stopped for longer periods of time than homogeneous groups. We also found that the degree of behavioural differences between the two strains helps to explain the observed non-additive changes in group behaviour. In particular, differences in locomotor activity level strongly influenced such synergistic behavioural changes. These results emphasise the importance of intraspecific diversity in group dynamics and suggest that genetic heterogeneity can improve group performance through the acquisition of latent behavioural traits.

Why did you choose JEB to publish your paper?

JEB is well known for publishing important studies in animal behaviour and physiology. I felt it was the right place to share our work, which looks at how genetic differences between individuals can influence behavioural dynamics. My research sits at the intersection of behaviour, ecology and genetics. JEB covers all of these areas, and I've often read papers in the journal that helped shape my ideas. Some key studies that inspired my experiment were also published in JEB, so it felt like a fitting journal for this article. This was my first time submitting a paper as the first author. After discussing with my supervisor and co-authors, I decided to submit it to JEB. As we had heard, the peer review process was clear, constructive and thorough. The feedback we received greatly helped improve the quality of our manuscript. I would like to take this opportunity to sincerely thank the editors and reviewers for the care and seriousness with which they evaluated our work.

What is the hardest challenge you have faced in the course of your research and how did you overcome it?

One of the biggest challenges I faced during this research was managing the multiple tasks involved in the behavioural experiments with flies. I had to rear a large number of fly strains while running behavioural assays at the same time. Each strain grows at a different pace – some breed quickly, others take longer to mature – and this variation, while biologically interesting, made planning quite difficult. Furthermore, I had to carefully control several factors that could affect behaviour, such as age, mating experience and developmental density. There were days when I had to give up on running an experiment because I couldn't get a sufficient number of individuals under the right conditions. Another major challenge was properly handling the large and complex behavioural dataset, which included many potential confounding factors. As animal behaviour can be noisy, I had to find ways to ensure reliable analysis. I learned many new skills, such as correcting tracking errors, removing outliers and statistically adjusting for variation caused by the time and date of each experiment. Overcoming these difficulties and getting my first paper accepted in JEB – a journal I deeply respect – has been one of the most rewarding experiences in my research journey so far.

What's next for you?

I am currently in the first year of my PhD programme at the Functional Ecology Laboratory, Chiba University. Over the next 2 years, I hope to deepen my expertise in behavioural ecology and further develop my skills in experimental design and data analysis. After completing my PhD, I would like to pursue a postdoctoral position abroad to expand my research perspectives and experience working in a different academic environment. Ultimately, my goal is to contribute to science on a global stage and build an international career in animal behaviour research.